The present invention relates to a display mode switching device, a display mode switching method, a display mode switching program, and a computer-readable recording medium recording the display mode switching program. More specifically, the present invention relates to a display mode switching device, a display mode switching method, a display mode switching program, and a computer-readable recording medium with the display mode switching program stored therein, which are configured to switch a display mode of a television set automatically between an overscan mode and an underscan mode.
Unlike a computer display monitor, about 10% in size of a screen is hidden at four edges by bezels and is not therefore displayed on a consumer television set. This display mode will be referred to as an “overscan” mode.
The overscan mode is suitable for a display on a television screen. However, this mode is not suitable for a display on a computer screen. The television screen mainly displays motion videos, in which important information is usually displayed in the center. On the contrary, the computer screen mainly displays still images, in which important information (such as icons or menu items) is often displayed close to four edges of the screen. Accordingly, when the computer screen is displayed on the television set, the entire computer screen is often scaled down to an effective display area of the television set. This display mode will be referred to as an “underscan” mode.
When a computer is connected to a television set, it is preferable to use the underscan mode to display a normal computer screen (such as a desktop screen of an operating system (OS)). However, it is preferable to use the overscan mode when playing a game or a digital versatile disk (DVD) movie, because it is more visible to spread the screen all over a display even if four edges of the screen are hidden by the bezels.
As described above, when a user connects the computer to the television set, the user may wish to display the normal computer screen in the underscan mode but the motion videos and the game in the overscan mode. However, it is cumbersome for the user to switch between the overscan mode and the underscan mode manually.
The following Patent Document 1 discloses a screen display range switching method of switching a display mode for a cathode ray tube (CRT) between the overscan mode and the underscan mode. This method is configured to display an image outputted from a computer in the underscan mode and to display an image outputted from a television tuner in the overscan mode by turning a switch. However, this method requires special hardware for switching between the overscan mode and the underscan mode. In addition, the image outputted from the computer will be always displayed in the underscan mode. Accordingly, even when a DVD is played on the computer, the image will be displayed in the underscan mode.
[Patent Document 1] Japanese Unexamined Patent Publication No. 61(1986)-176973
[Patent Document 2] Japanese Unexamined Patent Publication No. 2000-194347